This invention relates to roofing systems, and more particularly to prefabricated roof systems for installation on structures with substantially flat (horizontal) roof deck surfaces.
Flat roof installations present many problems not found with structures having inclined roof deck surfaces. In such installations the deck surface is typically not uniformly flat, but exhibits some depressed areas. Unless these areas are compensated for, installation of a conventional prefabricated roof system over such a deck surface may result in the collection or pooling of rain water in the locations of the depressions.
In the prior art, rapid installations of roof systems is rarely possible because substantial on-site construction is often called for. For example, where depressions in the roof deck are present (often indicated by leaks in the previous roof), it is common to construct a gabled structure atop the deck to provide some inclination.
Installation around obstructions such as roof mounted fixtures, vent pipes and the like, is time consuming and the resulting roof-fixture or roof-vent interface is often the site of future water leaks due to relative movement between the roof and the fixture or vent.
Frequently the new roof system is installed atop the pre-existing roof material without removing the same. In the past, the pre-existing roof material often included asbestos for fire retardation. Today it is generally required that the new installation encapsulate the asbestos for reasons of health and safety.